The invention applies advantageously but non-limitingly to apparatuses operating with an autonomous power supply, such as for example rechargeable batteries, and incorporating such devices. Wireless communication apparatuses, such as for example cellular mobile telephones or personal navigation devices, may be cited by way of indication.
Portable apparatuses are offering more and more services. This is true in particular for cellular mobile telephones which are incorporating numerous new multimedia applications such as Java applications, generation of polyphonic sounds, video functions, a digital camera, incorporated television functions, etc.
This escalation of new applications requires greater processing power, and this may be obtained in particular by data processing devices comprising several processing units such as processor cores.
But, an increase in processing power generally coincides with an increase in energy consumption.
This of course has a direct impact on the autonomy of the batteries.
A conventional energy reduction mechanism consists in placing a processing unit in a low consumption mode when this processing unit no longer has to perform any processing. And, each time that a processing is required, the processing unit exits its low consumption mode, performs the processing and re-enters the low consumption mode until the next processing required.
But, entry to and exit from the low consumption mode consume energy.
And, this consumed energy is all the more significant in multicore devices in which each core enters and exits its low consumption mode independently.